Pd and Pd–Ag Nanoparticles within a Macroreticular Basic Resin: An Efficient Catalyst for Hydrogen Production from Formic Acid Decomposition

Abstract

A basic resin bearing −N(CH3)2 functional groups within its macroreticular structure performed as an efficient organic support for the active Pd nanoparticles (NPs) responsible for the production of high-quality H2 via formic acid (HCOOH) decomposition at convenient temperature. Physicochemical characterization as well as the kinetic isotope effect (KIE) revealed that not only the formation of small Pd NPs but also cooperative action by the −N(CH3)2 groups within the resins play crucial roles in achieving efficient catalytic performances. In addition to the advantages such as simple workup procedure, free of additives, and superior catalytic activity compared with the conventional inorganic supports, the present catalytic system can suppress unfavorable CO formation of <5 ppm, which makes it an ideal hydrogen vector in terms of potential industrial application for proton-exchange-membrane fuel cells. Moreover, the basic resin support also provides Pd–Ag nanocatalyst from an aqueous solution of mixture of PdCl2 and AgNO3. The catalytic activities in the H2 production from formic acid decomposition were strongly dependent on the presence of Ag atoms and were shown to perform significantly better than the pure Pd and Ag catalysts.

Evolution of the PVP–Pd Surface Interaction in Nanoparticles through the Case Study of Formic Acid Decomposition

“…lower Pd accessibility resulted in few Pd active sites with strengthened catalytic ability). 24 According to previous studies, 37,39 the FA dehydrogenation reaction mechanism goes through a palladium-formate (Pd-[HCOO] -) intermediate, and therefore the catalytic performance is strongly dependent on the Pd surface features. The Pd surface deactivation due to the occupation of active sites by reaction intermediates compounds (such as H + , CO 2 , H 2 O and/or HCOO -) has been also studied by Hu et al.…”

“…34,35 The incorporation of Pd NPs on different supports (carbon, zeolites, MOFs or silica) has also been studied in the literature with different results depending on the nature of the support and the active phases features. [36][37][38][39][40][41] Herein the evolution of the PVP-Pd interaction over time as well as its repercussion on the final catalytic performance in the H 2 production from the dehydrogenation of FA was assessed by synthesising a series of catalysts based on PVP-capped Pd NPs supported on a meso-and macroporous SiO 2 . To this end, NPs with different PVP/Pd molar ratios and aging times were used.…”

AuPd–MnOx/MOF–Graphene: An Efficient Catalyst for Hydrogen Production from Formic Acid at Room Temperature

“…Hence, this alternative approach has attracted tremendous research interest. [ 5,6 ] Among the heterogeneous catalysts, Au, [ 7 ] Pd, [ 8 ] and their bimetallic [ 9 ] nanomaterials are the most effective catalysts for FA dehydrogenation. However, the high cost and scarcity of these elements greatly hinder large-scale practical applications of these noble-metal catalysts.…”

MnOx-Promoted PdAg Alloy Nanoparticles for the Additive-Free Dehydrogenation of Formic Acid at Room Temperature

“…In a recent study, Yamashita et al 45 reported that a resin bearing −N(CH 3 ) 2 acted as a significantly more efficient organic support material in the catalytic decomposition of FA than those bearing −SO 3 H, −COOH, and −OH for Pd or Ag@Pd NPs. Their mechanistic studies revealed that O−H bond cleavage in FA is facilitated by the −N(CH 3 ) 2 functionalities leading to the formation of metal-bound formate species along with a −[N(CH 3 ) 2 H] + species, followed by the dehydrogenation of the metal-bound formate, producing H 2 and CO 2 .…”